Showing posts with label Security. Show all posts
Showing posts with label Security. Show all posts

Monday, 3 June 2013

What is Firewall?How its help in network security?


Firewall is a device or a server which helps to protect our network nodes from unauthorised user's.

In simple words,

Firewall is a technique which is used to protect our private network from a public network i.e. Internet.



It is generally divided into 2 parts:-

  • Network firewall:-This firewall is used to check source and destination address of the network.
  • Application firewall:-It is also  used to check source and destination address of the network after network firewall.
Some attributes which are used by network firewall are service control,direction control,behaviour control and user control.Now I discuss some different-2 types of firewall.

Firewall is generally divided into 5 parts that are:-

1)Packet Filtering Router:-It is used to validates the source address of data and allows only authorised user's.

Some information used by Packet Filtering Router are:-

  • Source IP Address.
  • Destination IP Address.
  • Protocols etc.
Advantages and disadvantages of Packet Filtering Router:-

  1. It provide good security.
  2. It is cheap technique as compared to other types of firewall.
  3. It is very complex.
  4. Difficult to manage.
2)Stateful Inspection Firewall or Stateful Packet Inspection Firewall(SPI):-This firewall is use to protect our network from unauthorised user's.It is also provide Synchronisation,Acknowledgement etc.

3)Circuit Level Gateway:-It is used to validates the data packets  from a malicious code.It does not contain any specific proxy server.

4,5)Application Gateway and Guard Firewall:-

Application gateway firewall is also called as proxy server or proxy gateway.It is used to controls most of the protocols like http,ftp,mail protocol etc. from network.It provide good security as compared to SPI but it is very complex.

Guard firewall is the most complex firewall of all time.It is used to audit different-2 activities.

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